1. Field
The present disclosure relates generally to timing information and, in particular, to sending timing information in signals. Still more particularly, the present disclosure relates to sending timing information in optical signals.
2. Background
Digital communications are being used more and more to transmit data. Digital communication is the physical transfer of data over a communications channel. Communications channels may include, for example, without limitation, a wire, an optical fiber, a wireless communications channel, and/or some other suitable type of communications channel.
The data transferred over the communications channel is a digital series of bits impressed on an electromagnetic signal. For example, the electromagnetic signal may be an electrical voltage signal, a radio frequency signal, a microwave signal, an optical signal, an infrared signal, or some other suitable type of signal.
Timing information is an example of data that may be sent using digital communications. Typically, with currently available systems, timing information is sent using electrical wires, radio waves, and/or optical fibers. For example, in some applications, the timing information may be in the form of the leading edge or the trailing edge of an electrical or optical waveform or narrow pulse.
Optical communications using optical signals allow data to be transmitted at higher rates, as compared to using other forms of digital communications, such as radio waves or electrical wires. The higher rates for data transmission provide better resolution of the timing information.
Further, optical fibers used in optical communications reduce susceptibility of the transmission of data to electromagnetic interference. Optical communications also generate less electromagnetic interference and, thus, interfere less with other circuitry that is susceptible to electromagnetic interference.
However, currently available systems for sending timing information using optical signals may not provide the desired precision in the timing information.
Therefore, it would be advantageous to have a method and apparatus that takes into account at least some of the issues discussed above, as well as possibly other issues.